Blow and Banner (1962) drew a firm distinction between what they called a reduced final chamber and a true bulla, insisting that their new genus was characterized by the presence of a true bulla. However, this definition is not consistent with the current understanding of the term “bulla” (Hottinger, 2006). In Turborotalita, the “bulla” is essentially a final chamber that is reduced in size and displaced over the umbilicus more than would be expected from the general chamber sequence and sometimes possessing morphological features not seen on earlier chambers. The reduced final chamber often does not possess the characteristic shape of a “bulla”, especially among the early Neogene and Paleogene representatives of the genus. Hence, we emend the generic diagnosis to more specifically refer to the shape and position of the final chamber, which is applicable to all species in the genus. Fleisher (1974) and Kennett and Srinivasan (1983) suggested that the wall is microperforate, but the pore size is macroperforate (typically >2 µm in diameter) and the presence of true spines confirms the relationship of Turborotalita with other spinose macroperforate species. [Pearson & Kucera 2018]

Olsson and others (2006) traced Turborotalita to the middle Eocene Zone E9 (=P11) by assigning Globorotaloides carcoselleensis Toumarkine and Bolli to the genus. They suggested it may have evolved from Globoturborotalita, which itself appeared at the Paleocene / Eocene boundary. However, Koutsoukos (2014) described some exceptionally well-preserved assemblages from the Cretaceous/Paleogene transition off Rio de Janeiro, Brazil, including a new species which he called Praemurica nikolasi. We propose that this species is better assigned to Turborotalita on account of the possibly spinose wall (small holes described as minute pores may be spine holes) and general morphology, including particularly the ampullate final chamber. This species tends to have four and a half to five chambers in the final whorl. The highest occurrence of nikolasi was not determined by Koutsoukos (2014) because it extends to the top of that study section (Zone P1c). Other possible Paleocene occurrences include a specimen attributed by Blow (1979, pl. 83, fig. 1) to Globorotalia (Turborotalia) imitata Subbotina from Zone P2 and a specimen attributed by Olsson and others (1999, pl. 12, figs. 10-12) to Globanomalina imitata (Subbotina) from Zone P1b/c. Hence we hypothesize that Turborotalita is a distinct lineage that extends throughout the entire Cenozoic but has rarely been described from Paleogene sediments because of its small size, susceptibility to diagenetic alteration, and perhaps because workers had not expected to find it: resemblance to modern forms has been assumed to be evolutionary convergence rather than phylogenetic continuity. Future studies will hopefully determine the upward range of Turborotalita nikolasi and its relationship to other Turborotalita including T. carcoselleensis and T. quinqueloba. Genetically, modern T. quinqueloba groups with other spinose planktonic foraminifera but its 18S rDNA sequence is the most derived among the spinose species, and the phylogenetic position of the resulting extremely long branch is difficult to constrain (e.g., Aurahs and others, 2009:169; see also Darling and others, 2000, 2003), which is consistent with a deep phylogenetic divergence.  [Pearson & Kucera 2018]

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